Although
many kinds of insects have the word "fly" in their name
(butterfly, dragonfly), only the insects in the order Diptera are
the "True Flies." True flies are
different from most other insects because they have only 2 wings,
one on each side - most other insects have 4 wings, or no wings
at all. The back pair of wings on flies have evolved into
tiny structures called "halteres" (see below) which are
used during flight for balance.

Roll mouse over image: All true flies have a "haltere"
just
behind each wing on the thorax. Halteres help keepbalance while flying.

True fliesinclude house flies, mosquitoes, crane flies, and others.
They are some of the most common insects in Kentucky. The
many species of flies that live in Kentucky exhibit a vast array of
shapes, colors, and behaviors. Flies also have unusual mouthparts.
Instead of chewing their food, flies have evolved many different
kinds of liquid-feeding mouthparts, some of which mimic sponges (as
with house flies) and hypodermic needles (mosquitoes). Open
one of the Critter Files above to learn more.

Original document: 25 May 2004
Last updated: 17 November 2005

Photos courtesy R. Bessin and B. Newton, University of Kentucky
The Kentucky Critter
Files are maintained by Blake Newton, Department of Entomology, University
of Kentucky.
Contact: blaken@uky.edu